Pupils lack basic maths skills, such as knowing how to multiply, in about two-fifths of primary schools and half of secondary schools in Wales. That's according the school's inspectorate, ESTYN, following inspections that were carried out between 2010-2012.
The report says that pupils cannot apply advanced numeracy skills because they are struggling with the basics. Some pupils struggle with decimals, fractions and percentages, such as understanding the relationships between 2/5ths, 0.4 and 40%.
Other aspects that need to be improved are the tracking and monitoring of pupils' progress. Only a minority of primary schools and a few secondary schools have effective systems to track pupils' progress in numeracy beyond their maths lessons.
More top news
Members of the Welsh Guards have been training anti-poaching teams in Kenya to help stop the illegal trade in ivory.
Gusts of up to 70mph have been battering parts of Wales overnight and this morning, causing traffic problems in some areas.
Met office Yellow 'Be Aware' Warning of strong winds